From: Maor Gottlieb maorg@mellanox.com

Extend __sg_alloc_table_from_pages to support dynamic allocation of SG table from pages. It should be used by drivers that can't supply all the pages at one time.

This function returns the last populated SGE in the table. Users should pass it as an argument to the function from the second call and forward. As before, nents will be equal to the number of populated SGEs (chunks).

With this new extension, drivers can benefit the optimization of merging contiguous pages without a need to allocate all pages in advance and hold them in a large buffer.

E.g. with the Infiniband driver that allocates a single page for hold the pages. For 1TB memory registration, the temporary buffer would consume only 4KB, instead of 2GB.

Signed-off-by: Maor Gottlieb maorg@nvidia.com Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Leon Romanovsky leonro@nvidia.com --- drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 12 +- drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c | 15 +- include/linux/scatterlist.h | 43 +++--- lib/scatterlist.c | 160 +++++++++++++++----- lib/sg_pool.c | 3 +- tools/testing/scatterlist/main.c | 9 +- 6 files changed, 165 insertions(+), 77 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c index 12b30075134a..f2eaed6aca3d 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c @@ -403,6 +403,7 @@ __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj, unsigned int max_segment = i915_sg_segment_size(); struct sg_table *st; unsigned int sg_page_sizes; + struct scatterlist *sg; int ret;

st = kmalloc(sizeof(*st), GFP_KERNEL); @@ -410,13 +411,12 @@ __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj, return ERR_PTR(-ENOMEM);

alloc_table: - ret = __sg_alloc_table_from_pages(st, pvec, num_pages, - 0, num_pages << PAGE_SHIFT, - max_segment, - GFP_KERNEL); - if (ret) { + sg = __sg_alloc_table_from_pages(st, pvec, num_pages, 0, + num_pages << PAGE_SHIFT, max_segment, + NULL, 0, GFP_KERNEL); + if (IS_ERR(sg)) { kfree(st); - return ERR_PTR(ret); + return ERR_CAST(sg); }

ret = i915_gem_gtt_prepare_pages(obj, st); diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c index ab524ab3b0b4..f22acd398b1f 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c @@ -419,6 +419,7 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt) int ret = 0; static size_t sgl_size; static size_t sgt_size; + struct scatterlist *sg;

if (vmw_tt->mapped) return 0; @@ -441,13 +442,15 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt) if (unlikely(ret != 0)) return ret;

- ret = __sg_alloc_table_from_pages - (&vmw_tt->sgt, vsgt->pages, vsgt->num_pages, 0, - (unsigned long) vsgt->num_pages << PAGE_SHIFT, - dma_get_max_seg_size(dev_priv->dev->dev), - GFP_KERNEL); - if (unlikely(ret != 0)) + sg = __sg_alloc_table_from_pages(&vmw_tt->sgt, vsgt->pages, + vsgt->num_pages, 0, + (unsigned long) vsgt->num_pages << PAGE_SHIFT, + dma_get_max_seg_size(dev_priv->dev->dev), + NULL, 0, GFP_KERNEL); + if (IS_ERR(sg)) { + ret = PTR_ERR(sg); goto out_sg_alloc_fail; + }

if (vsgt->num_pages > vmw_tt->sgt.nents) { uint64_t over_alloc = diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 45cf7b69d852..c24cc667b56b 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -165,6 +165,22 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf, #define for_each_sgtable_dma_sg(sgt, sg, i) \ for_each_sg((sgt)->sgl, sg, (sgt)->nents, i)

+static inline void __sg_chain(struct scatterlist *chain_sg, + struct scatterlist *sgl) +{ + /* + * offset and length are unused for chain entry. Clear them. + */ + chain_sg->offset = 0; + chain_sg->length = 0; + + /* + * Set lowest bit to indicate a link pointer, and make sure to clear + * the termination bit if it happens to be set. + */ + chain_sg->page_link = ((unsigned long) sgl | SG_CHAIN) & ~SG_END; +} + /** * sg_chain - Chain two sglists together * @prv: First scatterlist @@ -178,18 +194,7 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf, static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, struct scatterlist *sgl) { - /* - * offset and length are unused for chain entry. Clear them. - */ - prv[prv_nents - 1].offset = 0; - prv[prv_nents - 1].length = 0; - - /* - * Set lowest bit to indicate a link pointer, and make sure to clear - * the termination bit if it happens to be set. - */ - prv[prv_nents - 1].page_link = ((unsigned long) sgl | SG_CHAIN) - & ~SG_END; + __sg_chain(&prv[prv_nents - 1], sgl); }

/** @@ -283,13 +288,15 @@ typedef void (sg_free_fn)(struct scatterlist *, unsigned int); void __sg_free_table(struct sg_table *, unsigned int, unsigned int, sg_free_fn *); void sg_free_table(struct sg_table *); -int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, - struct scatterlist *, unsigned int, gfp_t, sg_alloc_fn *); +int __sg_alloc_table(struct sg_table *, struct scatterlist *, unsigned int, + unsigned int, struct scatterlist *, unsigned int, + gfp_t, sg_alloc_fn *); int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); -int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, - unsigned int n_pages, unsigned int offset, - unsigned long size, unsigned int max_segment, - gfp_t gfp_mask); +struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt, + struct page **pages, unsigned int n_pages, unsigned int offset, + unsigned long size, unsigned int max_segment, + struct scatterlist *prv, unsigned int left_pages, + gfp_t gfp_mask); int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, unsigned int n_pages, unsigned int offset, unsigned long size, gfp_t gfp_mask); diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 5d63a8857f36..c200d3442f47 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -245,6 +245,7 @@ EXPORT_SYMBOL(sg_free_table); /** * __sg_alloc_table - Allocate and initialize an sg table with given allocator * @table: The sg table header to use + * @prv: Last populated sge in sgt * @nents: Number of entries in sg list * @max_ents: The maximum number of entries the allocator returns per call * @nents_first_chunk: Number of entries int the (preallocated) first @@ -263,17 +264,15 @@ EXPORT_SYMBOL(sg_free_table); * __sg_free_table() to cleanup any leftover allocations. * **/ -int __sg_alloc_table(struct sg_table *table, unsigned int nents, - unsigned int max_ents, struct scatterlist *first_chunk, - unsigned int nents_first_chunk, gfp_t gfp_mask, - sg_alloc_fn *alloc_fn) +int __sg_alloc_table(struct sg_table *table, struct scatterlist *prv, + unsigned int nents, unsigned int max_ents, + struct scatterlist *first_chunk, + unsigned int nents_first_chunk, gfp_t gfp_mask, + sg_alloc_fn *alloc_fn) { - struct scatterlist *sg, *prv; - unsigned int left; - unsigned curr_max_ents = nents_first_chunk ?: max_ents; - unsigned prv_max_ents; - - memset(table, 0, sizeof(*table)); + unsigned int curr_max_ents = nents_first_chunk ?: max_ents; + unsigned int left, prv_max_ents = 0; + struct scatterlist *sg;

if (nents == 0) return -EINVAL; @@ -283,7 +282,6 @@ int __sg_alloc_table(struct sg_table *table, unsigned int nents, #endif

left = nents; - prv = NULL; do { unsigned int sg_size, alloc_size = left;

@@ -308,7 +306,7 @@ int __sg_alloc_table(struct sg_table *table, unsigned int nents, * linkage. Without this, sg_kfree() may get * confused. */ - if (prv) + if (prv_max_ents) table->nents = ++table->orig_nents;

return -ENOMEM; @@ -321,10 +319,18 @@ int __sg_alloc_table(struct sg_table *table, unsigned int nents, * If this is the first mapping, assign the sg table header. * If this is not the first mapping, chain previous part. */ - if (prv) - sg_chain(prv, prv_max_ents, sg); - else + if (!prv) table->sgl = sg; + else if (prv_max_ents) + sg_chain(prv, prv_max_ents, sg); + else { + __sg_chain(prv, sg); + /* + * We decrease one since the prvious last sge in used to + * chain the chunks together. + */ + table->nents = table->orig_nents -= 1; + }

/* * If no more entries after this one, mark the end @@ -356,7 +362,8 @@ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) { int ret;

- ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, + memset(table, 0, sizeof(*table)); + ret = __sg_alloc_table(table, NULL, nents, SG_MAX_SINGLE_ALLOC, NULL, 0, gfp_mask, sg_kmalloc); if (unlikely(ret)) __sg_free_table(table, SG_MAX_SINGLE_ALLOC, 0, sg_kfree); @@ -365,6 +372,30 @@ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) } EXPORT_SYMBOL(sg_alloc_table);

+static struct scatterlist *get_next_sg(struct sg_table *table, + struct scatterlist *prv, unsigned long left_npages, + gfp_t gfp_mask) +{ + struct scatterlist *next_sg; + int ret; + + /* If table was just allocated */ + if (!prv) + return table->sgl; + + /* Check if last entry should be keeped for chainning */ + next_sg = sg_next(prv); + if (!sg_is_last(next_sg) || left_npages == 1) + return next_sg; + + ret = __sg_alloc_table(table, next_sg, + min_t(unsigned long, left_npages, SG_MAX_SINGLE_ALLOC), + SG_MAX_SINGLE_ALLOC, NULL, 0, gfp_mask, sg_kmalloc); + if (ret) + return ERR_PTR(ret); + return sg_next(prv); +} + /** * __sg_alloc_table_from_pages - Allocate and initialize an sg table from * an array of pages @@ -374,29 +405,49 @@ EXPORT_SYMBOL(sg_alloc_table); * @offset: Offset from start of the first page to the start of a buffer * @size: Number of valid bytes in the buffer (after offset) * @max_segment: Maximum size of a scatterlist node in bytes (page aligned) + * @prv: Last populated sge in sgt + * @left_pages: Left pages caller have to set after this call * @gfp_mask: GFP allocation mask * - * Description: - * Allocate and initialize an sg table from a list of pages. Contiguous - * ranges of the pages are squashed into a single scatterlist node up to the - * maximum size specified in @max_segment. An user may provide an offset at a - * start and a size of valid data in a buffer specified by the page array. - * The returned sg table is released by sg_free_table. + * Description: + * If @prv is NULL, allocate and initialize an sg table from a list of pages, + * else reuse the scatterlist passed in at @prv. + * Contiguous ranges of the pages are squashed into a single scatterlist + * entry up to the maximum size specified in @max_segment. A user may + * provide an offset at a start and a size of valid data in a buffer + * specified by the page array. * * Returns: - * 0 on success, negative error on failure + * Last SGE in sgt on success, PTR_ERR on otherwise. + * The allocation in @sgt must be released by sg_free_table. + * + * Notes: + * If this function returns non-0 (eg failure), the caller must call + * sg_free_table() to cleanup any leftover allocations. */ -int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, - unsigned int n_pages, unsigned int offset, - unsigned long size, unsigned int max_segment, - gfp_t gfp_mask) +struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt, + struct page **pages, unsigned int n_pages, unsigned int offset, + unsigned long size, unsigned int max_segment, + struct scatterlist *prv, unsigned int left_pages, + gfp_t gfp_mask) { - unsigned int chunks, cur_page, seg_len, i; + unsigned int chunks, cur_page, seg_len, i, prv_len = 0; + struct scatterlist *s = prv; + unsigned int table_size; + unsigned int tmp_nents; int ret; - struct scatterlist *s;

if (WARN_ON(!max_segment || offset_in_page(max_segment))) - return -EINVAL; + return ERR_PTR(-EINVAL); + if (IS_ENABLED(CONFIG_ARCH_NO_SG_CHAIN) && prv) + return ERR_PTR(-EOPNOTSUPP); + + tmp_nents = prv ? sgt->nents : 0; + + if (prv && + page_to_pfn(sg_page(prv)) + (prv->length >> PAGE_SHIFT) == + page_to_pfn(pages[0])) + prv_len = prv->length;

/* compute number of contiguous chunks */ chunks = 1; @@ -410,13 +461,17 @@ int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, } }

- ret = sg_alloc_table(sgt, chunks, gfp_mask); - if (unlikely(ret)) - return ret; + if (!prv) { + /* Only the last allocation could be less than the maximum */ + table_size = left_pages ? SG_MAX_SINGLE_ALLOC : chunks; + ret = sg_alloc_table(sgt, table_size, gfp_mask); + if (unlikely(ret)) + return ERR_PTR(ret); + }

/* merging chunks and putting them into the scatterlist */ cur_page = 0; - for_each_sg(sgt->sgl, s, sgt->orig_nents, i) { + for (i = 0; i < chunks; i++) { unsigned int j, chunk_size;

/* look for the end of the current chunk */ @@ -425,19 +480,41 @@ int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, seg_len += PAGE_SIZE; if (seg_len >= max_segment || page_to_pfn(pages[j]) != - page_to_pfn(pages[j - 1]) + 1) + page_to_pfn(pages[j - 1]) + 1) break; }

chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; - sg_set_page(s, pages[cur_page], - min_t(unsigned long, size, chunk_size), offset); + chunk_size = min_t(unsigned long, size, chunk_size); + if (!i && prv_len) { + if (max_segment - prv->length >= chunk_size) { + sg_set_page(s, sg_page(s), + s->length + chunk_size, s->offset); + goto next; + } + } + + /* Pass how many chunks might left */ + s = get_next_sg(sgt, s, chunks - i + left_pages, gfp_mask); + if (IS_ERR(s)) { + /* + * Adjust entry length to be as before function was + * called. + */ + if (prv_len) + prv->length = prv_len; + goto out; + } + sg_set_page(s, pages[cur_page], chunk_size, offset); + tmp_nents++; +next: size -= chunk_size; offset = 0; cur_page = j; } - - return 0; + sgt->nents = tmp_nents; +out: + return s; } EXPORT_SYMBOL(__sg_alloc_table_from_pages);

@@ -465,8 +542,9 @@ int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, unsigned int n_pages, unsigned int offset, unsigned long size, gfp_t gfp_mask) { - return __sg_alloc_table_from_pages(sgt, pages, n_pages, offset, size, - SCATTERLIST_MAX_SEGMENT, gfp_mask); + return PTR_ERR_OR_ZERO(__sg_alloc_table_from_pages(sgt, pages, n_pages, + offset, size, SCATTERLIST_MAX_SEGMENT, NULL, 0, + gfp_mask)); } EXPORT_SYMBOL(sg_alloc_table_from_pages);

diff --git a/lib/sg_pool.c b/lib/sg_pool.c index db29e5c1f790..c449248bf5d5 100644 --- a/lib/sg_pool.c +++ b/lib/sg_pool.c @@ -129,7 +129,8 @@ int sg_alloc_table_chained(struct sg_table *table, int nents, nents_first_chunk = 0; }

- ret = __sg_alloc_table(table, nents, SG_CHUNK_SIZE, + memset(table, 0, sizeof(*table)); + ret = __sg_alloc_table(table, NULL, nents, SG_CHUNK_SIZE, first_chunk, nents_first_chunk, GFP_ATOMIC, sg_pool_alloc); if (unlikely(ret)) diff --git a/tools/testing/scatterlist/main.c b/tools/testing/scatterlist/main.c index 0a1464181226..4899359a31ac 100644 --- a/tools/testing/scatterlist/main.c +++ b/tools/testing/scatterlist/main.c @@ -55,14 +55,13 @@ int main(void) for (i = 0, test = tests; test->expected_segments; test++, i++) { struct page *pages[MAX_PAGES]; struct sg_table st; - int ret; + struct scatterlist *sg;

set_pages(pages, test->pfn, test->num_pages);

- ret = __sg_alloc_table_from_pages(&st, pages, test->num_pages, - 0, test->size, test->max_seg, - GFP_KERNEL); - assert(ret == test->alloc_ret); + sg = __sg_alloc_table_from_pages(&st, pages, test->num_pages, 0, + test->size, test->max_seg, NULL, 0, GFP_KERNEL); + assert(PTR_ERR_OR_ZERO(sg) == test->alloc_ret);

if (test->alloc_ret) continue; -- 2.26.2

From: Tvrtko Ursulin tvrtko.ursulin@intel.com

A couple small tweaks are needed to make the test build and run on current kernels.

Signed-off-by: Tvrtko Ursulin tvrtko.ursulin@intel.com Signed-off-by: Maor Gottlieb maorg@nvidia.com Signed-off-by: Leon Romanovsky leonro@nvidia.com --- tools/testing/scatterlist/Makefile | 3 ++- tools/testing/scatterlist/linux/mm.h | 35 ++++++++++++++++++++++++++++ 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/tools/testing/scatterlist/Makefile b/tools/testing/scatterlist/Makefile index cbb003d9305e..c65233876622 100644 --- a/tools/testing/scatterlist/Makefile +++ b/tools/testing/scatterlist/Makefile @@ -14,7 +14,7 @@ targets: include $(TARGETS) main: $(OFILES)

clean: - $(RM) $(TARGETS) $(OFILES) scatterlist.c linux/scatterlist.h linux/highmem.h linux/kmemleak.h asm/io.h + $(RM) $(TARGETS) $(OFILES) scatterlist.c linux/scatterlist.h linux/highmem.h linux/kmemleak.h linux/slab.h asm/io.h @rmdir asm

scatterlist.c: ../../../lib/scatterlist.c @@ -28,4 +28,5 @@ include: ../../../include/linux/scatterlist.h @touch asm/io.h @touch linux/highmem.h @touch linux/kmemleak.h + @touch linux/slab.h @cp $< linux/scatterlist.h diff --git a/tools/testing/scatterlist/linux/mm.h b/tools/testing/scatterlist/linux/mm.h index 6f9ac14aa800..6ae907f375d2 100644 --- a/tools/testing/scatterlist/linux/mm.h +++ b/tools/testing/scatterlist/linux/mm.h @@ -114,6 +114,12 @@ static inline void *kmalloc(unsigned int size, unsigned int flags) return malloc(size); }

+static inline void * +kmalloc_array(unsigned int n, unsigned int size, unsigned int flags) +{ + return malloc(n * size); +} + #define kfree(x) free(x)

#define kmemleak_alloc(a, b, c, d) @@ -122,4 +128,33 @@ static inline void *kmalloc(unsigned int size, unsigned int flags) #define PageSlab(p) (0) #define flush_kernel_dcache_page(p)

+#define MAX_ERRNO 4095 + +#define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) + +static inline void * __must_check ERR_PTR(long error) +{ + return (void *) error; +} + +static inline long __must_check PTR_ERR(__force const void *ptr) +{ + return (long) ptr; +} + +static inline bool __must_check IS_ERR(__force const void *ptr) +{ + return IS_ERR_VALUE((unsigned long)ptr); +} + +static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr) +{ + if (IS_ERR(ptr)) + return PTR_ERR(ptr); + else + return 0; +} + +#define IS_ENABLED(x) (0) + #endif -- 2.26.2

From: Maor Gottlieb maorg@nvidia.com

Remove the implementation of ib_umem_add_sg_table and instead call to __sg_alloc_table_from_pages which already has the logic to merge contiguous pages.

Besides that it removes duplicated functionality, it reduces the memory consumption of the SG table significantly. Prior to this patch, the SG table was allocated in advance regardless consideration of contiguous pages.

In huge pages system of 2MB page size, without this change, the SG table would contain x512 SG entries. E.g. for 100GB memory registration:

Number of entries Size Before 26214400 600.0MB After 51200 1.2MB

Signed-off-by: Maor Gottlieb maorg@nvidia.com Signed-off-by: Leon Romanovsky leonro@nvidia.com --- drivers/infiniband/core/umem.c | 92 +++++----------------------------- 1 file changed, 12 insertions(+), 80 deletions(-)

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c index 01b680b62846..0ef736970aba 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -63,73 +63,6 @@ static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int d sg_free_table(&umem->sg_head); }

-/* ib_umem_add_sg_table - Add N contiguous pages to scatter table - * - * sg: current scatterlist entry - * page_list: array of npage struct page pointers - * npages: number of pages in page_list - * max_seg_sz: maximum segment size in bytes - * nents: [out] number of entries in the scatterlist - * - * Return new end of scatterlist - */ -static struct scatterlist *ib_umem_add_sg_table(struct scatterlist *sg, - struct page **page_list, - unsigned long npages, - unsigned int max_seg_sz, - int *nents) -{ - unsigned long first_pfn; - unsigned long i = 0; - bool update_cur_sg = false; - bool first = !sg_page(sg); - - /* Check if new page_list is contiguous with end of previous page_list. - * sg->length here is a multiple of PAGE_SIZE and sg->offset is 0. - */ - if (!first && (page_to_pfn(sg_page(sg)) + (sg->length >> PAGE_SHIFT) == - page_to_pfn(page_list[0]))) - update_cur_sg = true; - - while (i != npages) { - unsigned long len; - struct page *first_page = page_list[i]; - - first_pfn = page_to_pfn(first_page); - - /* Compute the number of contiguous pages we have starting - * at i - */ - for (len = 0; i != npages && - first_pfn + len == page_to_pfn(page_list[i]) && - len < (max_seg_sz >> PAGE_SHIFT); - len++) - i++; - - /* Squash N contiguous pages from page_list into current sge */ - if (update_cur_sg) { - if ((max_seg_sz - sg->length) >= (len << PAGE_SHIFT)) { - sg_set_page(sg, sg_page(sg), - sg->length + (len << PAGE_SHIFT), - 0); - update_cur_sg = false; - continue; - } - update_cur_sg = false; - } - - /* Squash N contiguous pages into next sge or first sge */ - if (!first) - sg = sg_next(sg); - - (*nents)++; - sg_set_page(sg, first_page, len << PAGE_SHIFT, 0); - first = false; - } - - return sg; -} - /** * ib_umem_find_best_pgsz - Find best HW page size to use for this MR * @@ -221,7 +154,7 @@ static struct ib_umem *__ib_umem_get(struct ib_device *device, struct mm_struct *mm; unsigned long npages; int ret; - struct scatterlist *sg; + struct scatterlist *sg = NULL; unsigned int gup_flags = FOLL_WRITE;

/* @@ -276,15 +209,9 @@ static struct ib_umem *__ib_umem_get(struct ib_device *device,

cur_base = addr & PAGE_MASK;

- ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL); - if (ret) - goto vma; - if (!umem->writable) gup_flags |= FOLL_FORCE;

- sg = umem->sg_head.sgl; - while (npages) { cond_resched(); ret = pin_user_pages_fast(cur_base, @@ -296,11 +223,17 @@ static struct ib_umem *__ib_umem_get(struct ib_device *device, goto umem_release;

cur_base += ret * PAGE_SIZE; - npages -= ret; - - sg = ib_umem_add_sg_table(sg, page_list, ret, - dma_get_max_seg_size(device->dma_device), - &umem->sg_nents); + npages -= ret; + sg = __sg_alloc_table_from_pages( + &umem->sg_head, page_list, ret, 0, ret << PAGE_SHIFT, + dma_get_max_seg_size(device->dma_device), sg, npages, + GFP_KERNEL); + umem->sg_nents = umem->sg_head.nents; + if (IS_ERR(sg)) { + unpin_user_pages_dirty_lock(page_list, ret, 0); + ret = PTR_ERR(sg); + goto umem_release; + } }

sg_mark_end(sg); @@ -322,7 +255,6 @@ static struct ib_umem *__ib_umem_get(struct ib_device *device,

umem_release: __ib_umem_release(device, umem, 0); -vma: atomic64_sub(ib_umem_num_pages(umem), &mm->pinned_vm); out: free_page((unsigned long) page_list); -- 2.26.2